Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Crystallization of membrane proteins in lipidic cubic phase (“LCP”) was introduced in 1996. This technique has proven to be crucial for elucidating structural mechanisms of membrane proteins. Success of using LCP for growing highly ordered crystals of challenging human membrane proteins can be attributed to at least two factors. LCP provides a more native-like membrane environment for proteins as opposed to a rather harsh environment associated with detergent micelles. Crystals grown in LCP have type I packing with protein molecules making contacts not only through hydrophilic but also through hydrophobic portions resulting in lower solvent content and better crystal ordering. The LCP crystallization technique yielded high-resolution structures of 38 different membrane proteins contributing 119 total entries to the Protein Data Bank. Structure determination with protein crystals in LCP at 3rd generation synchrotrons is still very challenging, since it is very difficult to grow large crystals in LCP. The crystal size is usually 5-10 micrometers with occasionally 50 micron crystals. Under prior art techniques, in order to determine the structure of protein crystals, the largest crystals have to be extracted and mounted in a sample holder, they are then frozen and exposed to a continuous X-ray beam. Due to the small size of the crystals, the signal obtained is low and radiation damage often terminates the experiment before useful high resolution data has been collected.